Skip to content

Instantly share code, notes, and snippets.

@alexey-bataev alexey-bataev/OpenMP.c Secret forked from clang-omp/OpenMP.c
Last active Dec 6, 2018

Embed
What would you like to do?
#include <assert.h>
#include <omp.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
const int N=2000;
int A[N][N], B[N][N];
int C[N][N], C1[N][N];
int main(void) {
int i, j, k;
double Start, End;
srand((int)time(NULL));
for (i = 0; i < N; ++i) {
for (j = 0; j < N; ++j) {
A[i][j] = rand() % 100;
B[i][j] = rand() % 100;
}
}
printf("---- Serial\n");
Start = omp_get_wtime();
for (i = 0; i < N; ++i) {
for (j = 0; j < N; ++j) {
int Sum = 0;
for (k = 0; k < N; ++k) {
Sum += A[i][k] * B[k][j];
}
C[i][j] = Sum;
}
}
End = omp_get_wtime();
printf("---- Serial done in %f seconds.\n", End - Start);
printf("---- Parallel\n");
Start = omp_get_wtime();
#pragma omp parallel for collapse(2) private(k)
for (i = 0; i < N; ++i) {
for (j = 0; j < N; ++j) {
int Sum = 0;
for (k = 0; k < N; ++k) {
Sum += A[i][k] * B[k][j];
}
C1[i][j] = Sum;
}
}
End = omp_get_wtime();
printf("---- Parallel done in %f seconds.\n", End - Start);
printf("---- Check\n");
for (i = 0; i < N; i++) {
for (j = 0; j < N; j++) {
assert (C[i][j] == C1[i][j]);
}
}
printf("Passed\n");
return 0;
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.
You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window. Reload to refresh your session.